3D printing integrates many technologies such as Computer-Aided Design (CAD), Computer-Aided Manufacturing (CAM), powder metallurgy and heat cladding. The basic principle is to generate 3D model with cross-sectional pattern and model the fused deposition and sintering path for the object to be formed. Heat source travels along the planned path and creates melt pool on the surface of the produced part, alloy powder is delivered to the melt pool and then cools off to form solid alloy. The heating source and the manufacturing station follows the predefined trajectory by CAD to produce the final product line by line and layer by layer. Different heating sources and processing technology can be used to produce final products with certain mechanical properties. 3D metal printing technology can be applied to many areas, such as mold manufacturing and repair, turbine blades repair, rapid prototyping, etc. Typically, 3D metal printing technology is thought to be complementary to the traditional manufacturing methods. It is good for materials that have high unit cost and products that are hard to manufacture with traditional methods (e.g. products with complex or irregular shape). Current 3D metal printing also has some limitations:                1) Current 3D printing technology often use powder material as the feeding materials, however, most of the materials have low efficiency of cladding, and are slow to process (e.g. alloy power materials).        2) Alloy powders are limited in type and are expensive, constraining the 3D Therefore, how to increase the types of raw alloy materials for 3D printing, improve efficiency, enhance quality, and reduce cost have become important research areas for the industry.        